A design of multi-layered location registration areas in microcellular systems

Multi-layered location registration areas are considered to minimize the control signals at boundary cells in the microcellular systems. The decision of multi-layered location registration (LR) areas is formulated as an integer programming problem by examining the regional subscriber densities, traffic flows and call arrival rates. By relaxing the constraints of forward and reverse control channels the problem is decomposed into a number of subproblems each of which corresponds to a layer. Each subproblem is solved via a modified graph partitioning algorithm. Feasible LR areas are obtained by considering the two relaxed constraints. Computational experiments are performed in a system with 80 microcells to investigate the performance of the proposed multi-layer scheme. The simulation results indicate that the two-layer scheme generally outperforms the one-layer and three-layer methods in view of control signals.